Magnetic-inductive device for the control of ferromagnetic reticles

ABSTRACT

The device object of this patent is composed of:—one box ( 1 ) which is U-shaped in its transversal section;—two guiding plates ( 2 ) for the magnets ( 4 );—two L-shaped rolled sections ( 3 ), which constitute the magnets ( 4 ) pole pieces;—various magnets ( 4 ) placed parallelly to the ferromagnetic insert ( 8 ) to be tested; each magnet ( 4 ) is placed parallel to the ferromagnetic insert ( 8 ) sliding direction with respect to the device and vice versa;—various measuring coils ( 5 ) placed in a housing ( 6 ), which is U-shaped in its transversal section;—a covering plate ( 7 ) fixed to box ( 1 ) in such a way to occupy the device side facing the insert ( 8 ) to be tested;—simple gears permitting to direct, in following times, the coils ( 5 ) parallelly to the different angles of the ferromagnetic insert ( 8 ) layers.

TECHNICAL FIELD

This invention consists in a device that allows a non-destructivetesting of the metal inserts made of ferromagnetic material in the formof wires and webs and is therefore particularly suitable for theinspection of tyres before being reconstructed.

BACKGROUND ART

The metal inserts in ferromagnetic material are used in differentapplications. They can be used as supporting elements of complexstructures or as being part of particular single elements.

For example, the covering of a tyre has an internal insert of steelwires, which are criss-crossed to strenghten the whole structure.

Worn out tyres are covered with a new tread allowing in this way theirrecycling. The reconstructed tyre achieves, in this way, security levelswhich can be compared to a new tyre from any point of view. Theapplication of stricts working procedures, from the acquisition andsuitability testing of the structure, to very accurate pressure controlsof the final product under working conditions, guarantees the highquality of the entire production process.

All wracks directed to reconstruction are in fact previously carefullyexamined through the utilization of suitable equipment, which verifiesthe conditions of suitability to reconstruction.

One of the main parameters taken into consideration is the integrity ofthe metal insert, which is usually tested through x-rays, ultrasoundsequipments or through scirografy.

Unfortunately the non-destructive testing of ferromagnetic metal insertsusing these appliances is rather expensive.

Two patents for non-destructive material tests are known, which make useof magnetism and electromagnetism. Patent US 2001/019263 describes anapparatus for testing the conditions of railroad rails. It consists in awave generator/transmitter, inclusive of a solenoid, and in a wavereceiver, also inclusive of a solenoid. Both have the same structure andeach of them is enclosed in a This device includes a U-shaped box,representing the base and sides of the device itself. A guiding platefor the magnets develops orthogonal to the device along each end of thebox. Each guiding plate is fixed to the two opposite sides. A L-shapedrolled section is in turn fixed to both the above mentioned guidingplates.

The box contains several magnets, the ends of which are held in theright position by the above mentioned guiding plates. Said rolledsections represent the magnet pole pieces. The box contains also severalcoils placed in a suitable shell. A covering plate is then fixed to thebox, in order to occupy the side of the device facing the metallicinsert to be examined. The measuring coils are positioned between themagnets and the metal insert, at the centre of the device. The box isequipped externally with at least a multiple signal power point. The boxand the covering plate avoid the contact of the magnets and coils,respectively, with the operator's hands or with the object to beexamined.

The inductor consists of pole pieces and permanent magnets made withlong-lasting high-stability materials and placed on one or more planesparallel to the ferromagnetic metal insert to be examined. Each magnetis placed parallely to the sliding direction of the metal insert withrespect to the device, object of this patent. When the device slides onthe ferromagnetic metal insert, it is correct to say that each magnet islocated parallely to the sliding direction of the device itself on themetal insert to be examined.

Each measuring coil is autonomously connected to the multiple signalpower point. The coils can also have simple gears, which permit theirrotation. It is therefore possible, later on, to direct them followingthe different angles of the metal layers with respect to the slidingaxis of the object to be tested.

This device permits a non-destructive testing of the ferromagneticinsert, both on the surface and internal part of an object. The devicecreates a magnetic field, parallel to that of the insert itself. Theposition and the possible presence of a damage are identified by one ormore coils that are placed in the magnetic field. The signals recordedby the coils are transmitted to a software obtaining a diagram whichunderlines the presence of defects (their position and extent).

BRIEF DESCRITION OF THE DRAWINGS

Further characteristics and advantages of this invention will becomeclearer with a description of some forms of execution of the device,preferred but not exclusive, which are illustrated indicatively, but notlimited to, in the enclosed drawings:

FIG. 1 shows a transversal section of a first device according to theinvention;

FIG. 2 shows a transversal section of a second device according to theinvention;

FIG. 3 shows a frontal view of a third device according to the inventionwithout covering plate;

FIG. 4 shows a transversal section of the device at FIG. 3, along theplane A-A;

FIG. 5 shows a transversal section of the device at FIG. 3, along theplane B-B;

FIG. 6 shows an enlarged frontal view of the coil and turning stand ofthe device at FIG. 3;

FIG. 7 shows an enlarged longitudinal view of the same coil and turningstand;

FIG. 8 shows a partial view of the device during a tyre testing;

FIGS. 9 and 10 show other partial enlarged frontal views of the deviceat FIG. 3 with a different positioning of the measuring coils;

FIG. 11 shows a partial enlarged frontal view of a device which hasdifferent possibilities of coil positioning.

MODE FOR CARRYING OUT THE INVENTION

More precisely the device on subject, in a first preferred embodimentshown in FIG. 1, is composed of an U-shaped box 1 in transversalsection, constituting the device base and sides.

A guiding plate 2 for the magnets develops orthogonal to the device,along each end of box 1. Each guiding plate 2 is fixed to the oppositesides of box 1. Box 1 has externally at least one multiple signal powerpoint and a stirrup for its fixing to the machinery. A L-shaped rolledsection 3 is in turn fixed to each one of the above mentioned guidingplates 2.

Box 1 contains several magnets 4, the ends of which are held in theright position by holes made in the above mentioned guiding plates 2.Rolled sections 3 are magnets' 4 pole pieces.

Box 1 also contains several coils 5, located in a particular shell 6,which is U-shaped in its transversal section. A covering plate 7 isfixed to box 1 in order to occupy the device side facing theferromagnetic insert 8 under examination. The coils 5 are placed betweenthe magnets 4 and the metal insert 8, at the centre of the device.

Box 1 and covering plate 7 avoid contacts of magnets 4 and coils 5,respectively, with the operator's hands and the object containing theferromagnetic insert 8.

The inductor is composed of the polar pieces and the permanent magnets 4made with long-lasting high-stability materials and placed on one ormore parallel planes to the ferromagnetic insert 8 to be tested. Eachmagnet 4 is placed parallel to the sliding direction of the insert 8with respect to the device object of this patent. When the device slideson the insert 8, it is possible to say that each magnet 4 is placedparallel to the sliding direction of the device on the ferromagneticinsert 8 to be tested.

Each coil 5 is autonomously connected to the multiple signal powerpoint. The device object of this patent can have a transversal fittedshape permitting to test inserts 8 having different shaped planes. Thedevice on subject, in a second preferred embodiment shown in FIG. 2,shows for example a transversal shape with a central plane and twoinclined sides. The permanent magnets 4 are placed on three planes, eachof them parallel to one plane of the metal ferromagnetic insert 8 to beexamined. Coils 5 can be equipped with simple gears permitting theirrotation.

In the device on subject, in a third preferred embodiment shown fromFIG. 3 to FIG. 10, each coil 5 is inserted in its stand 9. This standhas a pin 10 and a screwed roller 11. Each screwed roller 11 is crossedby a screwed bar 12. This bar has on both ends a knob 13 and a bushing14 sliding along the device side. The screwed bar 12 crossestransversally the entire device. Pins 10 are stuck in particular holesmade in the housing base 6 on which the coils 5 are placed. Pushing witha knob 13 the screwed bar towards the device internal part forces allscrewed rollers 11 to move in one direction letting rotate the differenthousings 9, which have pins 10 as their fulcrum. In this way it ispossible to direct the coils 5 parallely to one of the angles alongwhich are placed the metal layers of the ferromagnetic insert 8. Whenpulling the knob 13 towards the device external part, the coils 5 areforced to align parallely to another angle of the metal layer of theinsert 8.

Therefore the ferromagnetic insert 8 can be tested in following momentsalong all directions in which the metal layers composing the insertitself are directed.

In the device on subject, in a fourth preferred embodiment shown in FIG.11 each coil 5 has its own toothed rotating stand 15. This stand has apin stuck in a hole made in the housing base 6 on which are placed thecoils 5. A rack 16 or worm screw crosses the device transversally.

By moving a knob 17, placed at the rack end or at the worm screw end,the toothed turning stands 15 rotate and fit into the rack 16 or intothe worm screw itself. In this case too it is possible to test theinsert 8 along multiple directions.

1- Magnetic-inductive device for the control of ferromagnetic reticles,composed of a U-shaped box (1) in transversal section, which is the baseand sides of the device itself, several magnets (4) made withlong-lasting high-stability materials, several measuring coils (5), atleast one multiple signal power point placed externally to the box (1)and one stirrup for its fixing to the device; said device ischaracterized by the fact of moreover comprising: at least two guidingplates (2) for the magnets (4); each guiding plate (2) developsorthogonally to the device along each box (1) end and is fixed to theopposite two sides of the box (1) itself; two L-shaped rolled sections(3), each developping orthogonally to the device along each box (1) endand both fixed to one of the above mentioned guiding plates (2); saidrolled sections (3) constitute the magnets pole pieces (4); severalmagnets (4), the ends of which are held in the right position by holesmade in the guiding plates (2); the inductor is composed of the polarpieces and the permanent magnets (4), which are placed on one or moreparallel planes of the ferromagnetic insert to be tested; each magnet(4) is placed parallel to the ferromagnetic insert (8) sliding directionwith respect to the device itself; vice versa, when the device is toslide on the insert (8), it is possible to confirm that each magnet (4)is placed parallel to the device sliding direction on the insert (8);several coils (5) placed in a housing (6) which is U-shaped in itstransversal section; said coils (5) are placed between the magnets (4)and the ferromagnetic insert (8) at the centre of the device; each coil(5) is autonomously connected to the above mentioned multiple signalpower point; the signals recorded by the measuring coils (5) aretransmitted to a software, producing a diagram that underlines theposition and the extent of any damage found in the ferromagnetic insert(8); a covering plate (7) fixed to box (1) so that it occupies thedevice side facing the ferromagnetic insert (8) to be examined; simplegears which enable the coils (5) to rotate parallel, in following times,along all directions in which the insert (8) metal layers are directed.2- Magnetic-inductive device, according to claim 1, characterized by thefact of having a transversal shape suitable to test ferromagneticinserts (8) shaped along different planes; said permanent magnets (4)are placed on different planes, each one being parallel to a plane ofthe insert (8) to be examined. 3- Magnetic-inductive device, accordingto claim 1, characterized by the fact that said gears, enabling thecoils (5) to turn, consist of stands (9), each one housing a coil (5);each stand (9) has a pin (10) and a screwed roller (11); each screwedroller (11) is crossed by a screwed bar (12) having on at least one ofits ends a knob (13) and a bushing (14), which slides along the deviceside; said screwed bar (12) crosses the device transversally; the abovereferenced pins (10) are stuck in particular holes made in the housing(6) where the coils (5) are placed; by pushing with this knob (13) theconnected screwed bar (12) in one direction or in the other, all screwedrollers (11) are forced to move and they make turn the different stands(9), which have the pins (10) as fulcrum. 4- Magnetic-inductive device,according to claim 1, characterized by the fact that said gears,enabling the coils (5) to turn, are composed of toothed turning stands(15), each one housing a coil (5); each stand (15) has got a pin stuckin a hole drilled in the housing (6) on which the coils (5) are placed;a rack (16) or a worm screw crosses transversally the device; by pushingin one direction or in the other a knob (17) connected to a rack (16) ora worm screw, all toothed turning stands (15) are forced to rotate ontheir own pins.